DMTimer symbols not found

Hi All,

I am trying to write a kernel module that uses the Beagle Bone Black’s DMTimer to capture the trigger time of an input signal. When I try to install the kernel module, I receive the following errors:

[420546.913700] dmtimer_query: Unknown symbol omap_dm_timer_request_specific (err 0)

[422324.347351] dmtimer_query: Unknown symbol omap_dm_timer_stop (err 0)

It looks like my kernel version is not compiled with DMTimer support. I am using kernel “4.1.11-bone-rt-r16”. Would my problem be solved by switching to another precompiled kernel? If so, which kernel should I use? Do I need to recompile the linux kernel to include DMTimer support?

Thank you for the assistance,

Well it's built-in..


So maybe rebuild as a module?


Hi All,

Thank you for the insight. You are right, the kernel did have the omap_dm_timer symbols.

My error was that the symbols I required were exported as EXPORT_SYMBOL_GPL and I had not declared it as my license as MODULE_LICENSE(“GPL”) in my kernel module. As a result, my kernel module was not allowed to use those function symbols.